JP2007530724A - Photocurable composition - Google Patents

Abstract

An optical moulding process is disclosed comprising the sequential steps of: (a)(y) forming a layer of a photocurable composition; and (bXz) irradiating selected areas of the composition in the layer with radiation from a radiation source, thereby curing the composition in said selected areas and repeating the steps a) and b) on top of an earlier cured layer to form a three dimensional structure, wherein the radiation source used in step b) is a non-coherent source of radiation and wherein the photocurable composition comprises at least two curable components: (i) 45%-95% (and preferably at least 50%, more preferably at least 60%, e.g. at least 70%) by weight of the total curable components in the composition is a first component that is photocurable and that is such that, when cured in the presence of a photocuring initiator by exposure to UV radiation having an energy of 30 mJ/cm2, at least 90% of the component is cured within 50 milliseconds; and (ii) 5% to 55% (and preferably 10-40%, more preferably 15 to 30%, e.g. about 20%) by weight of the total curable components in the composition is a second component that results in the composition, on curing, shrinking, in a linear direction, by less than 3% and preferably that results in the composition having, after cure, a Tg of greater than 50° C., preferably at least 100° C. and more preferably at least 120° C.

Description

The present invention relates to photocurable compositions and methods for producing three-dimensional articles using rapid prototyping techniques. Three-dimensional articles produced from the photocurable composition of the present invention generally exhibit high performance characteristics.

BACKGROUND OF THE INVENTION Three-dimensional articles produced from layer-by-layer rapid prototyping technology (eg, stereolithography) using CAD have been commercially available for many years. The final mechanical and other [eg surface finish etc.] properties of such articles are derived from the materials used and the CAD layering system.

  For example, stereolithography systems, such as those described in US Pat. No. 4,575,330, produce 3D articles using complex photosensitive polymer mixtures addressed by UV lasers. Polymer blends used in such machines range from early acrylics suitable for concept modeling [eg US Pat. No. 6,043,323] to epoxy-acrylic hybrids [eg US Pat. Nos. 5,476,748, 6,136,497]. No. 6,136,497, No. 6,100,0007, No. 6,413,496, No. 6,099,787, No. 6,350,403, No. 5,437,964, No. 5,510,226, No. 5,494,618, No. 5705116], the latter being better Resulting in properties [eg, less shrinkage, higher flexural modulus, better elongation at break, higher tensile properties, and higher impact resistance], but typically in one or other properties A compromise is required. Nevertheless, the improved performance from epoxy-acrylic hybrids is useful for modeling specific technical properties.

  There are other systems that result in a layered three-dimensional system: laser sintering using thermoplastic powders, extrusion systems using extrudable pastes, jet printing directly or onto powders using fluids, etc. All of these material-mechanical systems have limitations in one area or the other, which limits the direct usefulness of the finally formed three-dimensional article. All of these systems also have limitations with respect to the speed to reach a three-dimensional article formed, especially from those using a laser scanning exposure process.

  There is a continuing need to achieve directly useful technical grade three-dimensional articles that are faster than previously possible.

  When such goods become available, from a service bureau-type retailer to the 'in-house' industrial design department, and from rapid prototyping to small to medium volume rapid manufacturing (short to medium volume). Rapid manufacturing) will show the prospect of expanding the market.

  In addition to these attributes, curing comparable to or better than the thermoplastic polymers used in previously produced articles [eg, by injection molding using polypropylene, ABS, polycarbonate, PEEK, etc. to name a few. Later properties are also highly desirable.

  Furthermore, there is a growing need for rapid prototyping materials and methods that produce stable three-dimensional articles over time. Traditionally, articles produced by rapid prototyping were initially very brittle, and the brittleness that increased with aging ended without notice. Since articles are only used for short-term applications, they often do not face the problem of brittleness.

  The present invention relates to a photocurable composition that can be used to produce three-dimensional articles having better and more stable properties in a shorter period of time than has been possible so far.

  Currently, in the production of three-dimensional articles by selectively irradiating selected areas of a continuous layer of photocurable composition, lasers are used as radiation sources to provide good cure rates. Other radiation sources that provide incoherent radiation cannot achieve cure rates similar to laser radiation, and the final UV flood during construction of the article and after removal from the bath in which the article is constructed Prior to curing (UV flood cure), the use of a composition that cures much faster is required to provide enough green strength to allow the article to be self-supporting. However, fast-curing polymers will soon become brittle and shrink substantially during curing, thereby reducing the accuracy of the model and curling part of the model.

Some prior art regarding thiolene-type compositions is as follows:
Example 1 of DE 44 40 819 A1 describes a composition containing 76.1 g of norbornene acrylate and 19.9 g of polythiol, which is cured with a He / Cd laser. The cured product has a high shrinkage level: 14.4%. Cured products obtained from compositions containing approximately equal amounts of norbornene acrylate and polythiol on a weight basis have lower shrinkage.

  U.S. Pat. No. 4,230,740 describes a composition containing a polyene component and a thiol, typically together with a reactive diluent and solvent, until the composition is applied to a substrate and crosslinked. Exposure to radiation, such as UV light, provides a non-yellowing coating on the substrate. This is far from constructing a three-dimensional article by optical molding.

  EP 0 492 953 A1 describes a stereolithographic method for building a three-dimensional article using a compound having a plurality of norbornene groups, a compound containing a plurality of thiol groups and a curable resin formulation containing a radical initiator. . Typically, a norbornyl compound and a thiol compound in a similar ratio [eg, 0.7: 1 to 1.3: 1] are used. There is no suggestion of producing 3D articles by non-laser technology. Norbornene compounds have a bad odor and it is not recommended to combine this with a odorous thiol. Furthermore, norbornene compounds are difficult to obtain commercially.

U.S. Pat. No. 4,230,740 describes thiolene compositions containing allyl cyanurate and thiol compounds, typically in similar weight ratios. Normally, it is described that the curing reaction is completed when heated at 450 ° F. for 15 minutes.
Some prior art of non-laser systems are:
Although WO 00/21735 describes non-laser methods, it is not disclosed that such methods would result in much improved mechanical properties from the resin.

  U.S. Pat. No. 6,500,355 describes a three-dimensional molding process that includes a spatial light modulator that regulates the electromagnetic radiation directed at the resin. There is no mention that non-laser exposure means may provide improved properties.

  Other possibilities are those described in EP1250997A1 and EP1253002A1.

  Other possibilities are as described in US 20040036200A1, US 20040207123A1, WO0301875, WO03 / 099947A1 and references therein, after injecting some UV curable fluid. Curing by laser irradiation is used.

  Another possibility is the use in direct printing, for example US Pat. No. 6,259,962 and related patents. This series of techniques generally discloses machine / equipment methods, but does not mention the effect of the system on the final properties that can be reached from such machines.

  Polymers can be broadly classified as follows.

  Thermoplastic resin: Reforms the original state after heating. It can be repeated many times.

Thermosetting resin: cured after heating. It only cures once. It cannot be reformed.
Thermoplastic resin Crystalline: Polymer arranged in a regular order Amorphous: Polymer thermosetting resin arranged randomly like a coil Polymerization of low molecular weight monomers due to polymer network Elastomers that can be either thermoplastic or thermoset Thermoset elastomers: natural and synthetic rubbers Thermoplastic elastomers: plastics that are very similar to rubber (EPDM, TPO, TPE)
Expensive equipment is required to produce laser radiation, and it is desirable to find other methods for curing photocurable compositions. Methods involving non-interfering actinic radiation require new photocurable compositions.

SUMMARY OF THE INVENTION The present invention provides methods and photocurable compositions that collectively provide a wide range of properties in three-dimensional articles formed using CAD layer techniques involving non-laser irradiation. . The properties obtained are preferably comparable to those obtained from conventional thermoplastic polymers.

According to a first aspect of the present invention, there is provided an optical molding method comprising a radiation source that is an incoherent radiation source, wherein the photocurable composition comprises at least two curable components:
i) 45 wt% to 95 wt% (and preferably at least 50 wt%, more preferably at least 60 wt%, such as at least 70 wt%) of the total curable component in the composition is the first component, The first component is photocurable and upon curing by exposure to UV radiation having an energy of 30 mJ / cm ² in the presence of a photocuring initiator, at least 90% of the component is cured within 50 milliseconds. And ii) 5% to 55% by weight of the total curable component in the composition (and preferably 10 to 40% by weight, more preferably 15 to 30% by weight, for example about 20% by weight). ) Is the second component, which results in shrinkage of the composition in the linear direction of less than 3% during curing, preferably higher than 50 ° C., preferably at least 100 ° C. after curing, More preferably results in a composition having a T _{g of} at least 120 ° C.
The method is provided.

The present invention is also a layerwise optical molding process using an incoherent radiation source, wherein the photocurable composition comprises at least two curable components:
iii) At least 70%, preferably at least 80%, more preferably at least 85% by weight of the total curable component in the composition is the first component, the first component being photocurable, light Such that upon curing by exposure to UV radiation having an energy of 30 mJ / cm ² in the presence of a curing initiator, at least 90% by weight of the component is cured within 50 milliseconds; and
iv) At least 5% by weight of the total curable component in the composition, preferably at most 30% by weight, preferably at most 20% by weight, preferably at most 15% by weight is the second component, the second component being cured A composition having a T _g of less than 3% in length in the linear direction, preferably having a T _g of higher than 50 ° C., preferably at least 100 ° C., more preferably at least 120 ° C. after curing. Bring the
The method is provided.

  Because the composition has a fast cure rate, it can be used with an incoherent radiation source and in doing so provides an article with good physical properties.

Preferably, at least 90% of the first component is cured by exposing the first component to UV radiation having an energy of 20 mJ / cm ² (more preferably 10 mJ / cm ² ) in the presence of a photocuring initiator. , Cure within 50 milliseconds.

  Preferably, at least 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88 or 89% by weight of the total curable component Is formed of the first component. Preferably, at least 90% by weight of the total curable component is formed of the first component. More preferably, at least 91, 92, 93, 94 or 95% by weight of the total curable component is formed of the first component.

  Preferably, at least 5, 6, 7, 8, 9 or 10% by weight of the total curable component in the composition is formed with the second component. Preferably, the second component is present in an amount comprised up to 15% by weight of the total curable component, preferably 5-15% by weight.

The first component is
(A) acrylates, such as mono, bis and higher degree functional acrylates, or mixtures thereof, wherein the acrylates preferably comprise at least one acrylate having a functionality of 2 or more,
(B) an amine base initiator, a base amplifier, and an anionically curable material, such as glycidyl epoxy or acrylate or an anhydride having a functionality of at least 2; base proliferation system), or (c) at least one cationically photocurable material, such as an epoxy (eg, cycloaliphatic epoxy or glycidyl epoxy), a cationic photocuring initiator, eg, tri-arylsulfonium SbF ₆ salt, And an acid amplifier, eg an acid amplified system comprising a tosylated compound, and (d) a polymer chain having two or more functional photoinitation groups, eg Polyester, polyether, polycarbonate, polybutadiene, polyurethane, polyalkane, or Resiloxanes, wherein the photoinitiating groups can react with curable components in the composition during exposure to radiation to form reactive groups that incorporate the polymer chains into the cured composition. The polymer chain is preferably a flexible and / or reinforcing chain,
One or more materials selected from the group consisting of:

  Photosensitive polymer systems that rely on photochemical release of basic species often have low photosensitivity. The base propagation system makes it possible to improve the photosensitivity and thus the cure rate of the photopolymer using a base catalyzed reaction.

 A base amplification product is a molecule that is easily degraded by base catalysis to liberate a base that is often an amine, which causes autocatalytic degradation. This process is called base multiplication. Acid propagation systems also exist for acid catalyzed reactions.

The second component is
(A) methacrylates, for example mono, bis or higher degree of functionality methacrylates, or mixtures thereof, preferably containing at least one methacrylate with at least 2 functionality,
(B) a compound having at least one terminal —SH, —NH or —OH group, such as an oligomeric liquid polysulfide, a mercaptan monomer, or a reactive alkane having at least one amine, hydroxy or thio end group, and (C) latent polyols, such as those derived from epoxies, or polyamines, such as those derived from blocked amines such as aliphatic amines derived from carbamates, or isocyanates that may be blended, or Hybrids with isocyanate groups and urethane groups, or (d) epoxies that may be accompanied by acid amplifiers, such as alicyclic epoxies or glycidyl epoxies, and (e) oxetanes or furans,
One or more materials selected from the group consisting of:

Preferably, the first component (fast-curing component) is
(I) acrylates, such as mono, bis and higher degree functional acrylates, or mixtures thereof, wherein the acrylate preferably comprises at least one acrylate having a functionality of 2 or more, Or
(Ii) a photo-polybase amplifier with a photo-amine initiator and an anionically photocurable material, for example an anhydride having a functionality of at least 2; An amine base growth system, or
(Iii) at least one cationically photocurable material, such as an epoxy (eg, cycloaliphatic epoxy), a cationic photocuring initiator, such as a tri-arylsulfonium SbF ₆ salt, and an acid amplifying material, such as a tosylated compound An acid amplification system comprising:
(Iv) polymer chains having two or more functional photoinitiators, such as polyesters, polyethers, polycarbonates, polybutadienes, polyurethanes, polyalkanes or polysiloxanes, wherein the photoinitiators are exposed to radiation In which a reactive group can be formed that reacts with the curable component in the composition to incorporate the polymer chain into the cured composition, the polymer chain being a flexible and / or reinforcing chain. Preferably,
One or more materials selected from the group consisting of:

Preferably, the second component (slow reaction component) is
(V) methacrylates, such as mono, bis or higher degree of functionality methacrylates, or mixtures thereof, preferably at least one methacrylate with at least 2 functionality,
(Vi) a compound having at least one terminal —SH, —NH or —OH group, such as an oligomeric liquid polysulfide, a mercaptan monomer, or a reactive alkane having at least one amine, hydroxy or thio end group, and
(Vii) i) Isocyanates that may be blended with latent polyols such as those derived from epoxies or from blocked amines such as polyamines such as aliphatic amines derived from carbamates Or
(Ii) a hybrid having an isocyanate group and a urethane group;
(Iii) epoxies that may be accompanied by acid amplifiers, such as alicyclic epoxies or glycidyl epoxies, and
(Iv) oxetane, furan, or ortho-spiro compound,
One or more materials selected from the group consisting of:

  The second component is a polythiol having two or more thiol groups per molecule, for example, a polythiol obtained by esterification of a polyol with α or β-mercaptocarboxylic acid (such as thioglycolic acid or β-mercaptopropionic acid), Alternatively, pentaerythritol tetramercaptoacetate or pentaerythritol tetrakis-β-mercaptopropionate (PETMP) can be included.

  Preferably, in the method according to the invention, the photocurable component comprises one or more softeners or reinforcements (eg (i) hydroxyl-containing compounds (eg polyesters, polyethers, polycarbonates or polyurethanes) or (ii) ) Hydroxyl version of thiol or amino equivalent) or reactive rubber / elastomer compounds (eg, polybutadiene with epoxy, acrylyl, amino, hydroxy, thiol or amino functional groups, or epoxy, acrylyl, hydroxyl, thiol) Or linear or cyclic polysiloxanes having amino functional groups).

  Using an incoherent radiation source to initiate curing in the various layers allows the entire layer of resin to be cured simultaneously rather than scanning the surface of the layer as occurs with a laser. There are advantages to the use of lasers that produce coherent radiation. An example of an instrument that can be used to create a three-dimensional article using an incoherent radiation source is described in WO 00/21735. In addition, the laser causes local heating of the composition, which leads to a heterogeneous reaction of the photoinitiator and tends to ablate the resin surface. Non-interfering exposure does not cause such problems.

According to a second aspect of the invention, on a weight percent basis,
1. At least two curable components:
(I) the first component in an amount of 60% to 90% by weight (and preferably 70 to 85% by weight) based on the total weight of the curable component in the composition, wherein the first component is photocurable. And when cured by exposure to UV radiation having an energy of 30 mJ / cm ² in the presence of a photocuring initiator, at least 90% of the component is cured within 100 milliseconds, preferably within 50 milliseconds. And (ii) curable in an amount of 5-30% by weight (and preferably 10-25% by weight, more preferably 10-20% by weight) of the total curable components in the composition. The second component, wherein the second component is a compound having at least one terminal thiol (-SH) group, such as an oligomeric liquid polysulfide, a mercaptan monomer, two or more thiols per molecule. A polythiol having an all group (for example, a polythiol obtained by esterification of a polyol with α or β-mercaptocarboxylic acid, such as thioglycolic acid or β-mercaptopropionic acid, or pentaerythritol tetramercaptoacetate, or pentaerythritol tetrakis-β -Mercaptopropionate (PETMP)),
2.0-10%, preferably 1-10% cationic photoinitiator,
3.0-10%, preferably 0.01-10, or preferably 1-10% radical photoinitiator,
4). 0 to 5%, preferably 0.001 to 5%, and 5.0 to 20% of auxiliary materials for pre-curing prior to use in the process, such as fillers, in particular submicron particles, 'Nano-sized' fillers such as siloxane particles, silica particles, nanoclays, nanometals, nanotubes,
An optical molding composition is provided.

The optical molding composition according to the invention is based on weight percent,
(A) At least two curable components:
(I) a first component in an amount of at least 80 wt%, preferably-at least 85 wt%, based on the total weight of the curable component in the composition, wherein the first component is photocurable and photocured Such that upon curing by exposure to UV radiation having an energy of 30 mJ / cm ² in the presence of an initiator, at least 90% by weight of the component is cured within 100 milliseconds, preferably within 50 milliseconds. ;and
(Ii) a curable second component in an amount of at least 5% by weight of the total curable component in the composition, wherein the second component is a compound having at least one terminal thiol (-SH) group, such as Oligomeric liquid polysulfides, mercaptan monomers, polythiols having two or more thiol groups per molecule (eg, obtained by esterification of polyols with α or β-mercaptocarboxylic acids such as thioglycolic acid or β-mercaptopropionic acid) Polythiol, or pentaerythritol tetramercaptoacetate, or pentaerythritol tetrakis-β-mercaptopropionate (PETMP)),
(B) 0-10%, preferably 1-10% cationic photoinitiator,
(C) 0.01-10% radical photoinitiator,
It is preferable to contain.

Preferably, the first component is cured by exposure to UV radiation having an energy of 20 mJ / cm ² (more preferably 10 mJ / cm ² ) in the presence of a photocuring initiator. It has a fast cure rate such that at least 90% by weight cures within 100 milliseconds (preferably within 50 milliseconds).

Preferably, the photocurable composition is
1 to 10% by weight of one or more softeners or reinforcements, such as (eg (a) (d) hydroxyl-containing compounds (eg polyester, polyether, polycarbonate or polyurethane) or (b) (e) hydroxyl Versions of thiol or amino equivalents) or reactive rubber / elastomer compounds (eg, polybutadiene with epoxy, acrylyl, amino, hydroxy, thiol or amino functional groups, or epoxy, acrylyl, hydroxyl, thiol or amino functional groups) Linear or cyclic polysiloxane)
Also contains.

Preferably, the photocurable composition comprises one or more softeners or reinforcements (eg, (f) a hydroxyl-containing compound (eg, polyester, polyether, polycarbonate or polyurethane) or (g) a hydroxyl version of a thiol or Amino equivalents), or reactive rubber / elastomer compounds (eg, epoxy, acrylyl, amino, hydroxy, thiol or polybutadiene with amino functional groups, or core shell reinforcements with reactive or compatible surfaces, or Also included are linear or cyclic polysiloxanes having epoxy, acrylyl, hydroxyl, thiol or amino functions.

  Preferably, the first component is an acrylate and the second component is a thiol-containing compound. When the first component includes a carbon-carbon double bond, such as an acrylate, it is preferred, and the ratio of double bond to thio group in the composition is 10: 1 to 2: 1, such as 9: 1 to 4: 1, for example in the range of 8: 1 to 5: 1.

  In one aspect, preferred curable compositions cure or polymerize with high sensitivity, particularly with incoherent irradiation, preferably less than 5%, more preferably less than 3%, most preferably after curing with a non-laser CAD system. Has a low shrinkage of about 0%. Along with these favorable low shrinkage properties, the composition after curing with a non-laser CAD system further has a variety of properties:

  The composition can include a single monomer, oligomer, reactive polymer, or mixture of suitable reactive components that produce the desired properties with a non-laser CAD system during curing.

  In another aspect, the present invention provides a photocurable composition comprising: (a) a first photosensitive polymer mixture that causes a rapid increase in viscosity during polymerization; and (b) a slower reaction than (a), Provided is a composition as described above comprising a second photosensitive polymer mixture that provides low shrinkage and high Tg properties after curing compared to the first mixture.

  In another aspect, the present invention provides a photocurable composition comprising: (a) a first photosensitive polymer mixture that causes a rapid increase in viscosity during polymerization; and (b) a slower reaction and a second after curing. Comprising a second photosensitive polymer mixture that results in low shrinkage and high Tg properties compared to one mixture, so that the final composite article formed from this mixture, inter alia by lamination techniques, is thermoplastic. A composition is provided.

  In yet another aspect, the present invention provides a photocurable composition comprising: (a) a first photosensitive polymer mixture that causes a rapid increase in viscosity during polymerization; and (b) a slower reaction after curing. Resulting in low shrinkage and high Tg properties compared to the first mixture, so that the final composite article formed from this mixture, inter alia by laminating techniques, has a thermoplastic which is stable over time [preferably under conditions of use In a composition comprising a second photosensitive polymer mixture, such as at a temperature below 120 ° C., no change in mechanical properties.

A method for producing a three-dimensional article in a continuous plurality of cross-sectional layers according to a model of the article, forming a first layer of a photocurable composition; Exposure to actinic radiation sufficient to cure the first layer in the imaged area in a pattern corresponding to the cross-sectional layer; a second of the photocurable composition above the cured first layer Exposing the second layer to actinic radiation sufficient to cure the second layer in the drawn area in a pattern corresponding to each cross-sectional layer of the model; and repeating the above two steps Also provides a method by forming a continuous layer as required to form a three-dimensional article, where the model is a corresponding other state-of-the-art machine such as stereolithography, laser sintering, 50% less time than extrusion system Produced. The model is preferably stable and has properties similar to the thermoplastics described above.
Detailed Description of the Invention "Three-dimensional article" refers to an article made from a cured resin composition of at least two layers. Thus, the production of the article has two components:
A: Drawing system or method B: Materials used in conjunction with A [one or more]
Is included.

  The final properties and production rate of the article are entirely the result of A and B interactions.

The present invention discloses an optimal route to more desirable properties in articles, as well as articles produced at higher speeds.
A: Drawing system or method This method includes several information means [based on CAD] and is provided to a mechanical system that deals with materials layer by layer and finally forms the final 'three-dimensional article' .

  The two layers can be the same or different according to the CAD information provided.

  The CAD information may be from a graphics design package or engineering design package, computer tomography image slice or ultrasound, to name a few. It can be from an ultrasound depth slice or from an ultra-toned microslice used in scanning electron microscopy.

  CAD information is used to activate the 'exposure' system to deal with layers of material. In current commercial systems, exposure systems use high power UV lasers such as in stereolithography [US Pat. No. 4,575,330] or high power infrared lasers such as in laser sintering. Other proposals include UV exposure through masks [Alan J Herbert, Solid Object Generation, Journal of Applied Photographic Engineering 8 (4), August 1982, pages 185-188, May 18, 1982. ]. More recently, a new concept using digitally controlled UV exposure of irradiation from conventional UV sources has been reported in WO 00/21735. In particular, the latter is described as being particularly useful for the production of larger models, which can be expected to produce models at a rate 10 times faster than previously possible.

  Other possibilities are those described in EP1250997A1 and EP1253002A1.

  Other possibilities are as described in US 20040036200A1, US 20040207123A1, WO0301875, WO03 / 099947A1 and references therein, after injecting some UV curable fluid. Curing by laser irradiation is used.

  Another possibility is the use in direct printing, for example US Pat. No. 6,259,962 and related patents. This series of techniques generally discloses machine / equipment methods, but does not mention the effect of the system on the final properties that can be reached from such machines.

  We use conventional radiation rather than laser beam irradiation [eg, from a UV laser source, ie YAG pumped with a diode at 355 nm and tripled frequency], which gives higher performance to articles after curing and forming Found to bring.

Surprisingly, selecting a particular material type takes full advantage of the fast addressability claimed in systems using conventional irradiation sources, such as those described in WO 00/21735, further helping the industry It is also possible to achieve higher properties than desired.
B: Material The material interacts with the exposure system and, in some way, distinguishes it from its original form and, in some way, deposits objects layer by layer according to programmed information. It is a composition that allows stitch stitching to occur and that converts to a form that is easily separated from the initial state of the material.

  Stereolithography uses a photosensitive polymer that is sensitive to UV [as discussed above].

  Without being bound by theory or in any way limiting, laser-based systems cause overproduction of starting species that promote polymerization, resulting in a short polymerization network and ultimately It is thought to limit the properties that can be reached by a laser system. Obviously, any attempt to reach a faster exposure rate [and thus achieve a faster reach to the formed three-dimensional article] by using a higher laser power is desirable for faster initiation of polymerization. Not only does it bring more seeds, it also increases the tendency for laser-induced heating / ablative effects to occur: non-linear delineation from expected performance Compromise in performance.

  Conventional irradiation systems can provide much better polymerization kinetics and thermodynamics; however, the speed and efficiency of the material to use the available onset energy is limited. This is especially true in layer-by-layer techniques for producing three-dimensional articles.

  Radical cured systems are clearly the fastest polymerization systems, such as acrylic resins compared to cationic [epoxy] systems, for use in exposure systems as described in WO 00/21735. It is considered suitable. However, these materials tend to shrink significantly [up to 8%]. Such shrinkage can cause partial deformation, internal stress, and the resulting loss of desirable properties.

  We disclose certain composition types that adapt quickly to the drawing process and still result in lower shrinkage, higher performance cured articles.

Common composition types include at least two polymerization systems that are compatible with each other:
(A) a first photocurable component comprising any photosensitive material that undergoes a viscosity change of at least 10 times the starting viscosity during exposure to irradiation energy at a maximum of 80 mJcm ⁻² , and (b) a first A second curable component that reacts slower than the mixture and results in a low shrinkage cured network that is compatible and integrated with that from (a).

  The starting viscosity for (a) is preferably about 1000 cps, more preferably 500 cps, most preferably less than 200 cps at 25 ° C.

  Preferably, the slower photosensitive second photosensitive polymer has a lower shrinkage than that from (a) [preferably less than 3%, more preferably 0%, ideally even slightly swell] and a high Tg. Bring. In order to achieve fracture impact stabilization, it is highly desirable to separate some integrated phases.

  Preferably, the total curable component in the composition is formed from only the first component and the second component, i.e. no other curable component is present or present in very small amounts. It is preferable that the composition does not contain a solvent.

These materials are illustrated by the following non-inclusive types:
1) Acrylic-methacrylic blends containing mono, bis and higher degrees of functionality, including inter-links such as urethanes, polyethers, polyesters, polyaromatics, perhydro-aromatics, etc. .

  The acrylic portion corresponds to component (a), and methacryl corresponds to type (b).

Some suitable types are available from CIBA, Sartomer and Rahn.
2) An acrylic-thio blend that additionally contains a methacrylic derivative as in 1). For example: oligomeric liquid polysulfide and / or mercaptan monomers with acrylates and / or alkenes, such as
http://torayfinechemicals.com/english/pori.html and
http://www.thioplasts.com/
What you can get at
3) Latency polyols [eg from epoxy] or polyamines [eg from blocked amines such as aliphatic amines from carbamates, J Mater. Chem, 2004, 14 (3), 336-343] An acrylic-isocyanate blend containing
Hybrid isocyanate functionalized (urethane) acrylate or isocyanate as a separate component, for example
http://www.bayer-ls.com/ls/lswebcms.nsf/id/001002 CHE
Bayer Roskydals as described in.
Reaction with moisture or
http://www.cibasc.com/view.asp?id=6822
Photolatent bases as described in 4-Use of Ciba 4) Cycloaliphatic and glycidyl epoxies with acid amplification and oxetane / furan 5) Hybrid acrylates / epoxys as different separate materials Or, if possible, one of the double functionalities within the same molecule.

The following section provides a general description of useful components belonging to the first and second components.
Acrylate-containing compound “(Meth) acrylate” refers to acrylate, methacrylate, or mixtures thereof. Acrylates can be used as all or part of the first component, whereas methacrylates can be used as the second component because they have a slower cure rate.

  The acrylate-containing compound is at least one poly (meth) acrylate, such as two, three, four or five, provided that the photocurable composition has less than 0.10 equivalents of acrylate groups per 100 grams of the composition. Functional, monomeric or oligomeric aliphatic, cycloaliphatic, or aromatic (meth) acrylates can be included. Bifunctional (meth) acrylates are preferred, and aliphatic or aromatic bifunctional (meth) acrylates are particularly preferred.

  Examples of di (meth) acrylates include alicyclic or aromatic diols such as 1,4-dihydroxymethylcyclohexane, 2,2-bis (4-hydroxy-cyclohexyl) propane, bis (4-hydroxycyclohexyl) methane , Hydroquinone, 4,4′-dihydroxybiphenyl, bisphenol A, bisphenol F, bisphenol S, ethoxylated or propoxylated bisphenol A, ethoxylated or propoxylated bisphenol F, and ethoxylated or propoxylated bisphenol S di ( And (meth) acrylate. This type of di (meth) acrylate is known and some are commercially available, for example Ebecryl 3700 (bisphenol-A epoxy diacrylate) (supplied by UCB Surface Specialties). Particularly preferred di (meth) acrylates are epoxy diacrylates based on bisphenol A.

  Alternatively, the di (meth) acrylate can be an acyclic aliphatic acrylic rather than alicyclic or aromatic. This type of di (meth) acrylate is known. Examples include compounds of formulas (FI) to (F-IV) of US Pat. No. 6,436,697, incorporated herein by reference. Other examples of possible di (meth) acrylates are compounds of formulas (FV) to (F-VIII) of US Pat. No. 6413697. Their preparation methods are also described in EP-A-0664680, which is incorporated herein by reference. Some compounds of formulas (FI) to (F-VIII) are commercially available.

  Poly (meth) acrylates suitable for the present invention include tri (meth) acrylate or higher functionality, provided that the photocurable composition has less than 0.10 equivalents of acrylate groups per 100 grams of the composition. Things can be mentioned. Examples are hexane-2,4,6-triol, glycerol, 1,1,1-trimethylolpropane, ethoxylated or propoxylated glycerol, and ethoxylated or propoxylated 1,1,1-trimethylolpropane. Tri (meth) acrylate. Another example is a hydroxyl-containing tri (meth) acrylate obtained by reacting a triepoxide compound (eg, triglycidyl ether of the above triol) with (meth) acrylic acid. Other examples are pentaerythritol tetraacrylate, bistrimethylolpropane tetraacrylate, pentaerythritol monohydroxytri (meth) acrylate, or dipentaerythritol monohydroxypenta (meth) acrylate.

  Poly (meth) acrylates can include multifunctional urethane (meth) acrylates. Urethane (meth) acrylates can be obtained, for example, by reacting a hydroxyl-terminated polyurethane with acrylic acid or methacrylic acid or by reacting an isocyanate-terminated prepolymer with a hydroxyalkyl (meth) acrylate to give a urethane (meth) acrylate. Can be prepared.

  Examples of suitable aromatic tri (meth) acrylates are the reaction products of trihydric phenols and triglycidyl ethers of phenols or cresol novolaks containing three hydroxyl groups with (meth) acrylic acid.

  For use in the first component, the acrylate-containing compound has at least one terminal and / or at least one pendant (ie, internal) unsaturated group and at least one terminal and / or at least one pendant hydroxyl group. The compound having The presence of hydroxy groups helps to achieve high viscosity changes. The photocurable composition of the present invention can contain more than one such compound. Examples of such compounds include hydroxy mono (meth) acrylate, hydroxy poly (meth) acrylate, hydroxy monovinyl ether, and hydroxy polyvinyl ether. Examples of those that are commercially available are dipentaerythritol pentaacrylate (SR® 399; supplied by SARTOMER Company), pentaerythritol triacrylate (SR® 444; supplied by SARTOMER Company) ), And bisphenol A diglycidyl ether diacrylate (Ebecryl 3700; supplied by UCB Surface Specialties).

  The following are examples of commercial poly (meth) acrylates: SR®295 (pentaerythritol tetraacrylate), SR®350 (trimethylolpropane trimethacrylate), SR®351 (tri) Methylolpropane triacrylate), SR (registered trademark) 367 (tetramethylolmethane tetramethacrylate), SR (registered trademark) 368 (tris (2-acryloxyethyl) isocyanurate triacrylate), SR (registered trademark) 399 (dipenta) Erythritol pentaacrylate), SR (registered trademark) 444 (pentaerythritol triacrylate), SR (registered trademark) 454 (ethoxylated (3) trimethylolpropane triacrylate), SR (registered trademark) 9041 (dipentaerythritol pentaacrylate ester) ), And CN® 120 (bisphenol A-Epic Rohi Dorin diacrylate) (supplied by all those mentioned above SARTOMER Company).

  Additional examples of commercially available acrylates include KAYARAD R-526 (hexanedioic acid, bis [2,2-dimethyl-3-[(1-oxo-2-propenyl) oxy] propyl] ester]); Sartomer 238 ( Hexamethylenediol diacrylate), SR (registered trademark) 247 (neopentyl glycol diacrylate), SR (registered trademark) 306 (tripropylene glycol diacrylate), Kayarad R-551 (bisphenol A polyethylene glycol diether diacrylate), Kayarad R-712 (2,2′-methylenebis [p-phenylenepoly (oxyethylene) oxy] diethyl diacrylate), Kayarad R-604 (2-propenoic acid, [2- [1,1-dimethyl-2- [ (1-oxo-2-propenyl) oxy] ethyl] -5-ethyl-1,3-dioxane-5-yl] methyl ester), Kaya rad R-684 (dimethylol tricyclodecane diacrylate), Kayarad PET-30 (pentaerythritol triacrylate), GPO-303 (polyethylene glycol dimethacrylate), Kayarad THE-330 (ethoxylated trimethylolpropane triacrylate), DPHA -2H, DPHA-2C and DPHA-21 (dipentaerythritol hexaacrylate), Kayarad D-310 (DPHA), Kayarad D-330 (DPHA), DPCA-20, DPCA-30, DPCA-60, DPCA-120, DN-0075, DN-2475, Kayarad T-1420 (ditrimethylolpropane tetraacrylate), Kayarad T-2020 (ditrimethylolpropane tetraacrylate), T-2040, TPA-320, TPA-330, Kayarad RP-1040 (penta Erythritol ethoxylate tetraacrylate), R-011, R-300, R-205 (methacrylic acid, zinc salt, same as SR (registered trademark) 634) (Nippon Kayaku Co., Ltd.), Aronix M-210, M -220, M-233, M-240, M-215, M-305, M-309, M-310, M-315, M-325, M-400, M-6200, M-6400 (Toagosei Chemical Industry Co, Ltd.), light acrylate BP-4EA, BP-4PA, BP-2EA, BP-2PA, DCP-A (Kyoeisha Chemical Industry Co., Ltd.), New Frontier BPE-4, TEICA, BR-42M, GX-8345 (Daichi Kogyo Seiyaku Co., Ltd.), ASF-400 (Nippon Steel Chemical Co.), Ripoxy SP-1506, SP-1507, SP-1509, VR-77, SP-4010, SP-4060 ( Showa Highpolymer Co., Ltd.), NK Ester A-BPE-4 (Shin-Nakamura Chemical Industry Co., Ltd.), SA-1002 (Mitsubishi Chemical Co., Ltd.), Viscoat-195, Viscoat-230, Viscoat-260, Viscoat-310, Viscoat-214HP, Viscoat-295, Viscoat-300, Viscoat-360, Viscoat-GPT, Viscoat-400, Viscoat-700, Viscoat-540, Viscoat-3000, Viscoat-3700 (Osaka Organic Chemical Industry Co., Ltd.).

The photocurable composition of the present invention can include a mixture in which the acrylate-containing compound is combined with a methacrylic derivative, the latter being a second component that reacts slower.
Polythiol-containing compound capable of forming all or part of the second component The polythiol component of the composition of the present invention can be any compound having two or more thiol groups per molecule. Suitable polythiols are described in U.S. Pat. No. 8 stage 76 row to the ninth stage 46, line of No. 3,661,744; described in U.S. Patent No. 3,445,419 and No. 4,289,867; seventh stage 40-57 rows of U.S. Patent No. 4,119,617 Yes. Particularly preferred are polythiols obtained by esterification of polyols with α or β-mercaptocarboxylic acids such as thioglycolic acid or β-mercaptopropionic acid. Particularly preferred polythiols are pentaerythritol tetramercaptoacetate and pentaerythritol tetrakis-β-mercaptopropionate (PETMP).

  The ratio of polyene and polythiol component can vary greatly. In general, the ratio of ene groups to thiol groups is preferably 10: 1 to 2: 1, for example 9: 1 to 4: 1, for example 8: 1 to 5: 1, but in some cases outside this range Can be effectively employed without departing from the present invention.

Curable compositions using the compounds of the present invention can include both bifunctional ene compounds and bifunctional thiol compounds, but at least some of these components are cross-linked products upon curing. It will be understood that more than two functional groups should be contained per molecule to yield That is, the sum of the average number of ene groups per molecule of polyene and the average number of coreactive thiol groups per molecule of polythiol should exceed 4 when a crosslinked and cured product is desired. is there. This sum is referred to as the “overall reactive functionality” of the composition.
Epoxy-containing compounds Any epoxy-containing compound is suitable for the present invention: Some examples of epoxy-containing compounds suitable for use in the present invention are described in US Pat. No. 5,476,748, Patent Publication 2001/0046642 A1. And U.S. Patent Publication No. 2002/0160309, all of which are incorporated herein by reference. Specifically, for use as component (a), it is further catalyzed / amplified by an acid labile amplifying material [as exemplified in J Mat Chem, 2001, 11, 295-301]. An epoxy compound that can be promoted to ring-open by a photogenerated acid, such as that from a tri-arylsulfonium SbF ₆ salt, in a process that can be prepared.

  Preferred epoxy-containing compounds suitable for the present invention as component (a) are non-glycidyl epoxies. Such epoxies include one or more epoxide compounds in which the epoxide group forms part of an alicyclic or heterocyclic ring system. Others include epoxy-containing compounds with at least one epoxycyclohexyl group bonded directly or indirectly to a group containing at least one silicon atom. These epoxies can be linear, branched, or cyclic in structure. An example is disclosed in US Pat. No. 5,639,413, which is incorporated herein by reference. Still other include epoxides containing one or more cyclohexene oxide groups and epoxides containing one or more cyclopentene oxide groups. An example is disclosed in US Pat. No. 3,117,099, which is incorporated herein by reference.

  Particularly suitable non-glycidyl epoxies include the following bifunctional non-glycidyl epoxide compounds in which the epoxide group forms part of an alicyclic or heterocyclic ring system: bis (2,3-epoxycyclopentyl) ) Ether, 1,2-bis (2,3-epoxycyclopentyloxy) ethane, 3,4-epoxycyclohexyl-methyl 3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-6-methyl-cyclohexylmethyl 3, 4-epoxy-6-methylcyclohexanecarboxylate, di (3,4-epoxycyclohexylmethyl) hexanedioate, di (3,4-epoxy-6-methylcyclohexylmethyl) hexanedioate, ethylenebis (3,4 Epoxycyclohexanecarboxylate, ethane All di (3,4-epoxycyclohexylmethyl) ether, vinylcyclohexene dioxide, dicyclopentadiene diepoxide or 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclohexane-1,3 -Dioxane, and 2,2'-bis- (3,4-epoxy-cyclohexyl) -propane.

  Highly preferred bifunctional non-glycidyl epoxies include alicyclic bifunctional non-glycidyl epoxies. Such epoxies suitable for the present invention include 3,4-epoxycyclohexyl-methyl 3,4-epoxycyclohexanecarboxylate and 2,2'-bis- (3,4-epoxy-cyclohexyl) -propane. .

  The most preferred difunctional non-glycidyl epoxy suitable for the present invention is 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate.

  The photocurable composition preferably comprises, as component (b), polyglycidyl ether, poly (β-methylglycidyl) ether, polyglycidyl ester, poly (β-methylglycidyl) ester, poly (N-glycidyl) compound, and One or more epoxy-containing compounds that are poly (S-glycidyl) compounds can be included.

  Synthetic methods and examples of polyglycidyl ether, poly (β-methyl glycidyl) ether, polyglycidyl ester and poly (β-methyl glycidyl) ester are disclosed in US Pat. No. 5,972,563, which is incorporated herein by reference. Incorporated for reference.

  Particularly important representatives of polyglycidyl ethers or poly (β-methylglycidyl) ethers are those based on phenols: monocyclic phenols, such as those based on resorcinol or hydroquinone, or polycyclic phenols, For example, bis (4-hydroxyphenyl) methane (bisphenol F), 2,2-bis (4-hydroxyphenyl) propane (bisphenol A), or a condensate obtained under acidic conditions of phenols or cresols and formaldehyde Based on, for example, phenol novolac and cresol novolac. Examples of preferred polyglycidyl ethers include trimethylolpropane triglycidyl ether, polypropoxylated glycerol triglycidyl ether, and 1,4-cyclohexanedimethanol diglycidyl ether. Examples of particularly preferred polyglycidyl ethers include diglycidyl ethers based on bisphenol A and bisphenol F and mixtures thereof.

  The poly (N-glycidyl) compound can be obtained, for example, by dehydrochlorination of the reaction product of epichlorohydrin and an amine containing at least two amine hydrogen atoms. These amines can be, for example, n-butylamine, aniline, toluidine, m-xylylenediamine, bis (4-aminophenyl) methane or bis (4-methylaminophenyl) methane. However, other examples of poly (N-glycidyl) compounds include cycloalkylene ureas such as N, N′-diglycidyl derivatives of ethylene urea or 1,3-propylene urea, and hydantoins such as 5,5-dimethylhydantoin. N, N′-diglycidyl derivatives may be mentioned.

  Examples of poly (S-glycidyl) compounds are di-S-glycidyl derivatives derived from dithiols such as ethane-1,2-dithiol or bis (4-mercaptomethylphenyl) ether.

  It is also possible to employ epoxy-containing compounds in which the 1,2-epoxide groups are attached to different heteroatoms or functional groups. Examples of these compounds include N, N, O-triglycidyl derivatives of 4-aminophenol, glycidyl ether / glycidyl ester of salicylic acid, N-glycidyl-N ′-(2-glycidyloxypropyl) -5,5- Examples include dimethylhydantoin or 2-glycidyloxy-1,3-bis (5,5-dimethyl-1-glycidylhydantoin-3-yl) propane.

  Other epoxide derivatives such as vinylcyclohexene dioxide, vinylcyclohexene monooxide, 3,4-epoxycyclohexylmethyl acrylate, 3,4-epoxy-6-methylcyclohexylmethyl-9,10-epoxystearate, 1,2- Bis (2,3-epoxy-2-methylpropoxy) ethane or the like may be employed.

  The use of a liquid adduct obtained by previously reacting the epoxy-containing compound as described above with a curing agent for epoxy resin is also conceivable. It is of course possible to use a liquid mixture of liquid or solid epoxy resins for the new compound.

  The following is an example of a commercial epoxy product suitable for use in the present invention: UVA 1500 (3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate; supplied by UCB Chemicals Corp.) Heloxy 48 (trimethylolpropane triglycidyl ether; supplied by Resolution Performance Products LLC), Heloxy 107 (diglycidyl ether of cyclohexanedimethanol; supplied by Resolution Performance Products LLC), Uvacure 1501 and 1502, Uvacure 1531, Uvacure 1532, Uvacure 1533, Uvacure 1534, and Uvacure 1561 and Uvacure 1562 are also required; Union Carbide, Danbury, Connecticut; the alicyclic epoxide supplied by UCB Surface Specialties, Smyrna, Georgia) UVR-6105 (3,4-epoxy supplied by Corp. Cyclohexylmethyl-3,4-epoxycyclohexanecarboxylate), UVR-6100 (3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate), UVR-6110 (3,4-epoxycyclohexylmethyl-3, 4-epoxycyclohexanecarboxylate), UVR-6128 (bis (3,4-epoxycyclohexyl) adipate), UVR-6200, UVR-6216 (1,2-epoxyhexadecane), and alicyclic epoxides include Araldite CY179 ( 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate) and PY284 and Celoxide 2021 (3,4-epoxycyclohexyl) methyl-3,4-epoxycyclohexylcarboxylate), Celoxide 2021 P (3'-4 '-Epoxycyclohexane) methyl 3 -4′-epoxycyclohexyl-carboxylate), Celoxide 2081 (3′-4′-epoxycyclohexane) methyl 3′-4′-epoxycyclohexyl-carboxylate modified caprolactone), Celoxide 2083, Celoxide 2085, Celoxide 2000 , Celoxide 3000, Cyclomer A200 (3,4-epoxy-cyclohexylmethyl-acrylate), Cyclomer M-100 (3,4-epoxy-cyclohexylmethyl-methacrylate), Epolead GT-300, Epolead GT-302, Epolead GT-400 , Epolead 401, and Epolead 403 (all marketed by Daicel Chemical Industries Co., Ltd.).

The photocurable composition of the present invention may include a mixture of the above epoxy-containing compounds.
Hydroxyl-containing compounds The photocurable compositions of the present invention may contain one or more hydroxyl-containing compounds used as softeners or reinforcements; the corresponding thiol and amino counterparts can also be used. Preferably, the hydroxyl-containing compound is difunctional. More preferably, the bifunctional hydroxyl-containing compound is a polyether polyol. Most preferably, the polyether polyol is polytetramethylene ether glycol (“polyTHF”). The polyTHF preferably has a molecular weight of about 250 to about 2500. The polyTHF can be terminated with hydroxy, epoxy, or ethylenically unsaturated groups (one or more). Polytetramethylene ether glycol is commercially available in the Polymeg® type (Penn Specialty Chemicals). Preferably, the photocurable composition of the present invention comprises Polymeg® 1000, which is a linear diol with a nominal molecular weight of 1000 g.
Radical photoinitiator The radical photoinitiator can be selected from those commonly used to initiate radical photopolymerization. Examples of radical photoinitiators include benzoins such as benzoin, benzoin ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether and benzoin phenyl ether, and benzoin acetate; acetophenones such as acetophenone, 2,2 -Dimethoxyacetophenone and 1,1-dichloroacetophenone; benzyl ketals such as benzyl dimethyl ketal and benzyl diethyl ketal; anthraquinones such as 2-methylanthraquinone, 2-ethylanthraquinone, 2-tertbutylanthraquinone, 1-chloroanthraquinone And 2-amylanthraquinone; triphenylphosphine; benzoylphosphine oxide, such as 2, , 6-trimethylbenzoyl-diphenylphosphine oxide (Luzirin® TPO); bisacylphosphine oxide; benzophenones such as benzophenone and 4,4′-bis (N, N′-dimethylamino) benzophenone; thioxanthones And xanthones; acridine derivatives; phenazine derivatives; quinoxaline derivatives; 1-phenyl-1,2-propanedione 2-O-benzoyloxime; 4- (2-hydroxyethoxy) phenyl- (2-propyl) ketone (Irgacure 2959; Ciba Specialty Chemicals); 1-aminophenyl ketone or 1-hydroxyphenyl ketone, such as 1-hydroxycyclohexyl phenyl ketone, 2-hydroxyisopropyl phenyl ketone, phenyl 1-hydroxyisopropyl ketone, and 4 Isopropyl phenyl 1-hydroxy-isopropyl ketone.

  Preferably, the radical photoinitiator is cyclohexyl phenyl ketone. More preferably, the cyclohexyl phenyl ketone is 1-hydroxyphenyl ketone. Most preferably, the 1-hydroxyphenyl ketone is 1-hydroxycyclohexyl phenyl ketone, such as Irgacure 184 (Ciba Specialty Chemicals).

For stereolithography using a laser, it is preferred to select a cationic photoinitiator and a radical photoinitiator, such that their concentrations are such that the cure depth at standard laser speed is from about 0.1 to about 2.5 mm. It is preferable to adjust so as to achieve the absorption capacity. “Stereolithography” is a method of producing solid objects from computer-aided design (“CAD”) data. The CAD data of the object is first created and then sliced into thin cross sections. A laser beam that traces the pattern of the cross section through the liquid plastic is controlled by a computer to solidify a thin layer of plastic corresponding to the cross section. The solidified layer is again coated with liquid plastic, the other cross section is traced with a laser beam, and the other plastic layer is cured on top of the previous layer. This process is continued layer by layer to complete the molded product. A desired molded article can be constructed in a few hours. This method is described in US Pat. No. 5,476,748, US Publication No. 2001/0046642, and Paul F. Jacobs, Rapid Prototyping & Manufacturing 69-110 (1992), the entire contents of which are described herein. Incorporated as a reference in.
Cationic Photoinitiator The cationic photoinitiator can be selected from those commonly used to initiate cationic photopolymerization. Examples include onium salts with weakly nucleophilic anions, such as halonium salts, iodosyl salts, sulfonium salts, sulfoxonium salts or diazonium salts. Metallocene salts are also suitable as photoinitiators. Onium salt and metallocene salt photoinitiators are described in US Pat. No. 3,708,296; “UV-Curing, Science and Technology” (edited by SP Pappas, Technology Marketing Corp.) and KK Dietliker, Chemistry & Technology of UV & EB Formulations for Coatings, Inks & Paints, Vol. 3 (PK Oldring 1991), each of which is incorporated herein by reference.

  Examples of commercial cationic photoinitiators include UVI-6974, UVI-6976, UVI-6970, UVI-6960, UVI-6990 (Dow Corp.), CD 1010, CD-1011, CD-1012 (Sartomer Corp. ), Adekaoptomer SP150, SP-151, SP-170, SP-171 (Asahi Denka Kogyo Co., Ltd.), Irgacure 261 (Ciba Specialty Chemicals Corp.), CI-2481, CI-2624, CI-2639, CI2064 (Nippon Soda Co, Ltd.) and DTS-102, DTS-103, NAT-103, NDS-103, TPS-103, MDS-103, MPI-103, BBI-103 (Midori Chemical Co, Ltd.) Can be mentioned. Most preferred are UVI-6974, CD-1010, UVI-6976, Adekaoptomer SP-170, SP-171, CD-1012 and MPI-103. Particularly preferred is a mixture of S, S, S, S′-tetraphenylthiobis (4,1-phenylene) disulfonium dihexafluoroantimonate and diphenyl (4-phenylthiophenyl) sulfonium hexafluoroantimonate. . The cationic photoinitiator can be used either alone or in combination of two or more.

Other compounds The photocurable composition of the present invention may contain various other components. Examples of such components include, for example, modifiers, reinforcing agents, stabilizers, antifoaming agents, leveling agents, thickeners, flame retardants, antioxidants, pigments, dyes, fillers and combinations thereof. A combination is mentioned.

  Preferably, the composition is substantially free of solvents that can be detrimental to the correct construction of 3D articles.

  The photocurable composition may contain a reactive filler as described in WO03 / 089991.

  The photocurable composition of the present invention can also contain one or more stabilizers. Preferred stabilizers are butylated hydroxytoluene (“BHT”), 2,6-di-tert-butyl-4-hydroxytoluene, and hindered amines such as benzyldimethylamine (“BDMA”), N, N-dimethylbenzyl. It is an amine.

  In one embodiment of the present invention, the photocurable composition includes an acrylic-containing compound as the first component (a), a thio-containing compound as the second component (b), and a radical photoinitiator.

The photocurable composition of the present invention is formulated to allow the production of three-dimensional articles with better performance when irradiated with conventional (incoherent) UV rather than laser UV. The photocurable composition of the present invention is more suitable for UV incoherent irradiation than laser UV.
Exposure system:
Another aspect of the present invention is a method for producing a three-dimensional article in a continuous plurality of cross-sectional layers according to a model of the article, forming a first layer of a photocurable composition. Exposing the first layer to actinic radiation sufficient to cure the first layer in the drawn area in a pattern corresponding to each cross-sectional layer of the model; light above the cured first layer; Forming a second layer of curable composition; exposing the second layer to actinic radiation sufficient to cure the second layer in the drawn area in a pattern corresponding to each cross-sectional layer of the model; And including a method by repeating the above two steps to form a continuous layer as required to form a three-dimensional article, wherein the exposure system includes a non-coherent light source, such as xenon. Xenon fusion lamp or light-emitting diode bar It is preferable to use such irradiation.

  Other methods include methods in which the curable fluid is sprayed directly onto the substrate or onto the powder so that the sprayed material is cured by electromagnetic radiation. The compositions claimed herein that combine a reactive material that reacts quickly and a reactive material that prevents shrinkage are also useful in such methods.

  Those skilled in the art will appreciate that the various aspects described above and in the experimental section below are intended to be representative and that the invention may be practiced differently than what is specifically described herein. It will be understood that it is still within the scope of the claims and their equivalents.

Comparative Example Using Laser Exposure Method The general procedure used to make a three-dimensional article with a stereolithography apparatus, such as SLA 7000, is as described in WO 03/089991. In the case of Example 2, the SLA exposure conditions are
Dp = 5.5; Ec = 3.5
Met.

  The comparative example was also performed using the flood exposure method with a resin sample placed in a mold.

The examples of the present invention were carried out using the method of WO 00/21735, courtesy of DICON A / S, Lystrup, Denmark.
Example:
1) Acrylic composition
Resin for stereolithography SL5131, an acrylic formulation from Huntsman Advanced Materials, was drawn on SL 7000 equipment according to the method of WO 00/21735. The results are shown below. Clearly, there is an improvement in the value of tensile stress.

2) Acrylic-polythiol composition 1
The following compounds were mixed for 2 hours at room temperature in a brown bottle under a yellow light.

  Ebecryl 8402 is a urethane diacrylate component having a Mw of 1000 according to US20040181007.

  The composition was drawn on a SL 7000 instrument according to the method of WO 00/21735. Overall, performance was significantly improved by conventional UV cure exposure via a layer-by-layer CAD system compared to a laser-based stereolithography system.

CAD systems using non-laser irradiation provide the best combination of properties. Lamination also yields better results than simply mould curing the resin.
3) Comparison between Composition 1 and Stereocol 9300
Stereocol 9300 is a complete acrylic composition containing an acrylic derivative and urethane acrylate.

  Therefore, this type of resin corresponds to a comparative resin that does not have a second component that reduces the problem of shrinkage with acrylic derivatives.

Test bars for Stereocol 9300 and acrylic-thiolene composition 1 were made according to the following design, with the system described in WO 00/21735, courtesy of Dicon, Lystrup, Denmark.
Bar for tensile test

Charpy test bar

  The results of these test bars are shown below:

Examples 4-8:
The following formulation was made by tumbling the ingredients [wt%] for 6 hours at room temperature in a brown jar with a tight sealing cap.

  The viscosity of the fluid was measured at 25 ° C. using a Brookfield HBTD Viscometer (0.8 ° cone spindle).

Mold cure sample: The formulation was poured into a silicone mold and cured with UV (Fusion Systems F450 lamp, 120 W / cm ² , 7.5 seconds). The molded article was removed from the mold, turned over, and cured again with UV (Fusion Systems F450 lamp, 120 W / cm ² , 7.5 seconds). Tensile properties were measured using a Stable Micro Systems TA-HDi Texture Analyzer at a test speed of 0.08 mm / s and a grip distance of 55 mm.

  Example 4 shows that the properties are synergistically improved by combining the acrylic component [Example 5] and the cationic component [Example 6]. Example 4 does not meet the criteria exposed using the method of WO 00/21735 (on borderline). However, these formulations can have better utility in systems that cure after selective jetting of the curable fluid, for example by UV irradiation.

Claims (12)

A layer-by-layer optical molding process using an incoherent radiation source, wherein the photocurable composition comprises at least two curable components:
(I) at least 70%, preferably at least 80%, more preferably at least 85% by weight of the total curable component in the composition is the first component, the first component being photocurable; Such that upon curing by exposure to UV radiation having an energy of 30 mJ / cm ² in the presence of a photocuring initiator, at least 90% by weight of the component cures within 50 milliseconds; and (ii) At least 5% by weight of the total curable component in the composition, preferably at most 30% by weight, preferably at most 20% by weight, preferably at most 15% by weight, is the second component, which is Resulting in a shrinkage of the composition of less than 3% in length in the linear direction, preferably higher than 50 ° C. after curing, preferably at least 100 ° C., more preferably at least 120 ° C. _Resulting in a composition having T _g .
Said method. When at least 90% by weight of the first component is cured by exposing the first component to UV radiation having an energy of 20 mJ / cm ² (more preferably 10 mJ / cm ² ) in the presence of a photocuring initiator, 50 The method of claim 1, wherein the method cures in milliseconds. The first component is
(A) (h) acrylates, for example mono, bis and higher functional acrylates, or mixtures thereof, wherein the acrylate comprises at least one acrylate having a functionality of 2 or more Is preferred, or
(I) an amine photoinitiator, a base amplifier, and an anionically curable material such as an glycidyl epoxy or acrylate or an anhydride having a functionality of at least 2; j) at least one cationically photocurable material such as an epoxy (eg alicyclic epoxy), a cationic photocuring initiator such as a tri-arylsulfonium SbF ₆ salt, and an acid amplifying material such as a tosylated compound. An acid amplification system, and (d) (k) a polymer chain having two or more functional photoinitiating groups, such as polyester, polyether, polycarbonate, polybutadiene, polyurethane, polyalkane, or polysiloxane, wherein The photoinitiating group reacts with the curable component in the composition during exposure to radiation. It is possible to form reactive groups that incorporate the polymer chains into the cured composition, and the polymer chains are preferably flexible and / or reinforcing chains.
The method of claim 1, comprising one or more materials selected from the group consisting of: The second component is
(A) (l) methacrylates, for example mono-, bis- or higher-functional methacrylates, or mixtures thereof, preferably containing at least one methacrylate with a functionality of at least 2;
(B) (m) a compound having at least one terminal —SH, —NH or —OH group, such as an oligomeric liquid polysulfide, a mercaptan monomer, or a reactivity having at least one amine, hydroxy or thio end group An alkane, and (c) (n) (i) a latent polyol, such as one derived from an epoxy, or one derived from a blocked amine such as an aliphatic amine derived from a polyamine, such as a carbamate, An optionally blended isocyanate, or
(Ii) a hybrid having an isocyanate group and a urethane group;
(Iii) epoxies that may be accompanied by acid amplifiers, such as alicyclic epoxies or glycidyl epoxies, and (iv) oxetane, furan, or ortho-spiro compounds,
The method according to any one of claims 1 to 3, comprising one or more materials selected from the group consisting of:   A polythiol obtained by esterification of a polyol with a second component, a polythiol having two or more thiol groups per molecule, for example, α or β-mercaptocarboxylic acid (such as thioglycolic acid or β-mercaptopropionic acid), 5. The method of claim 4, comprising pentaerythritol tetramercaptoacetate or pentaerythritol tetrakis-β-mercaptopropionate (PETMP).   The photocurable component is one or more softeners or reinforcements (eg (a) (v) hydroxyl-containing compounds (eg polyester, polyether, polycarbonate or polyurethane) or (b) (vi) hydroxyl versions of thiols Or amino equivalents), or reactive rubber / elastomer compounds (eg, epoxy, acrylyl, amino, hydroxy, thiol, or polybutadiene with amino functional groups, or core-shell reinforcement with reactive or compatible surfaces, or epoxy, acrylyl) , A linear or cyclic polysiloxane having a hydroxyl, thiol or amino function). On a weight percent basis,
(A) (o) at least two curable components:
(I) a first component in an amount of at least 80 wt%, preferably-at least 85 wt%, based on the total weight of the curable component in the composition, wherein the first component is photocurable and photocured Such that upon curing by exposure to UV radiation having an energy of 30 mJ / cm ² in the presence of an initiator, at least 90% by weight of the component is cured within 100 milliseconds, preferably within 50 milliseconds. And (ii) a curable second component in an amount of at least 5% by weight of the total curable component in the composition, wherein the second component is a compound having at least one terminal thiol (-SH) group; For example, oligomeric liquid polysulfide, mercaptan monomer, polythiol having two or more thiol groups per molecule (for example, α or β-mercaptocarboxylic acid) Such as thioglycolic acid or β- mercapto polythiol obtained by esterification of polyols with acid or pentaerythritol tetra-mercapto acetate, or pentaerythritol tetrakis -β- mercaptopropionate, (PETMP)),
(B) (p) 0-10%, preferably 1-10% cationic photoinitiator,
(C) (q) 0-10%, preferably 0.01-10% radical photoinitiator,
(D) (r) 0 to 5%, preferably 0.001 to 5%, and (e) (s) 0 to 20% of auxiliary materials for pre-curing prior to use in the process, for example, Fillers, in particular sub-micron particles, 'nano-sized' fillers such as siloxane particles, silica particles, nano clays, nano metals,
An optical molding composition comprising: 50 milliseconds when at least 90% by weight of the first component is cured by exposure to UV radiation having an energy of 20 mJ / cm ² (more preferably 10 mJ / cm ² ) in the presence of a photocuring initiator. 8. The composition of claim 7, which cures within. The first component is
(A) (t) acrylates, such as mono, bis and higher degree functional acrylates, or mixtures thereof, wherein the acrylate comprises at least one acrylate having a functionality of 2 or more preferable,
(B) an amine base propagation system comprising (u) an amine photoinitiator, a photo-polybasic amplifying material, and an anionically photocurable material, such as an acrylate having a functionality of at least 2, or ( c) (v) at least one cationically photocurable material such as an epoxy (eg cycloaliphatic epoxy), a cationic photocuring initiator such as a tri-arylsulfonium SbF ₆ salt, and an acid amplifying material such as tosyl An acid amplification system comprising a compound,
The composition according to claim 7 or 8, comprising one or more materials selected from the group consisting of: The photocurable composition is
1-10% by weight of one or more softeners or reinforcements, for example (eg (a) (w) hydroxyl-containing compounds (eg polyester, polyether, polycarbonate or polyurethane) or (b) (x) hydroxyl Versions of thiol or amino equivalents) or reactive rubber / elastomer compounds (eg, polybutadiene with epoxy, acrylyl, amino, hydroxy, thiol or amino functionality, or epoxy, acrylyl, hydroxyl, thiol or amino functionality) The composition according to any one of claims 7 to 9, which also contains a linear or cyclic polysiloxane.   The composition according to any one of claims 7 to 10, wherein the first component is an acrylate.   The first component includes a carbon-carbon double bond, such as an acrylate, and the ratio of double bond to thio group in the composition is 10: 1 to 2: 1, such as 9: 1 to 4: 1, such as 8: The composition according to any one of claims 7 to 11, which is 1 to 5: 1.